1. Field of the Invention
The present invention relates to a method for transmitting data between a base station and at least one remote unit, such as a transponder or remote sensor, with an electromagnetic wave, onto which information packets of different symbols are modulated, wherein the information packets have at least one header section and one data section, wherein the symbols are explicitly defined in the header section of at least one information packet, and wherein in a subsequent data section, data are encoded by means of the symbols and transmitted.
Moreover, the invention relates to a device for transmitting data by means of an electromagnetic wave, onto which information packets of different symbols can be modulated, with a base station and at least one remote unit, such as a transponder or remote sensor, wherein the information packets have at least one header section and one data section, wherein the symbols are explicitly defined in the header section of at least one information packet, and wherein in a subsequent data section, data can be encoded by means of the symbols and transmitted.
2. Description of the Background Art
In general, methods for transmitting data between a base station and a remote unit, for example, a transponder or a remote sensor—designated herein together as “tag”—are used in order to perform an identification within a so-called authentification process. The basis for bidirectional data transmission between the tag and base station thereby forms a data protocol or transmission protocol, which specifies the number of information symbols, among other things, for example, the significant values per data bit, and defines the identity of the individual symbols. A corresponding method—particularly related to an advantageous structure of the header section—is the subject of EP 1417631, which corresponds to U.S. Publication No. 2003133435, and which is herein incorporated by reference.
Within the scope of international collaboration in the field of radio frequency identification (RFID), in the past so-called “(minimal) air interfaces” in the form of data protocol interfaces between the tag and base station have been defined, cf. “Specification for an RFID Air Interface, EPCglobal, EPC™ Radio Frequency Identity Protocols, Class-1 Generation-2 UHF RFID, Protocol for Communications at 860 MHz-960 MHz, version 1.0.7” of Sep. 27, 2004, which is abbreviated as EPCglobal. In agreements of the type, it is not subsequently possible to readily extend a once specified protocol in a simple manner with additional commands or the like. Another complicating factor is that in many cases in protocols of the types, code sequences are reserved for later official extensions. Concept considerations for EPCglobal are mentioned here as an example: based on a basic protocol concept (Class 1), other protocol classes (Class 2 and Class 3) with additional functionalities, such as sensor applications or security-relevant applications, are to be developed. For extensions beyond this standard, however, on the basis of the mentioned protocol concept, either so-called customer commands or certain fixed preset code sequences are to be considered, cf. EPCglobal, p. 11.
Such approaches usually do not function in open RFID systems with at least one base station and tags of a different (and variable) type and number, in which different customers are provided with one and the same tag solution. In fact, in such cases, the employed transmission protocol can basically offer customer-specific codes; however, complications arise if a plurality of customers receive, in addition, tags from different manufacturers, because a certain customer-specific command can only address one customer in each case. Especially if several customers each wish to use a customer-specific solution, consequently this can no longer be represented by a single uniform code. For this reason, novel solution mechanisms are required for platform solutions, in which a command code is to be extended cost-effectively or a switch to a modified operating mode (multiprotocol capability), such as full-duplex operation, is to be made possible.